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Modification of the guitar bracing using optimization

Pilch Adam

Vibrations in Physical Systems

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2023

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Vol. 34, nr 2

art. no. 2023221

EN

The form of modern guitars were shaped by Spanish luthiers in the XIX century. Especially Antonio de Torres Jurado is the one, whose designs are an inspiration for modern constructions. From the very beginning, guitars are struggling with not sufficient sound levels for all the desired applications. Apart from electroacoustic amplification, there were several attempts to modify the construction of the sound hole or the soundboard. Higher sound pressure levels were often connected with distorted sound, sometimes not acceptable to musicians. In this paper, inequalities in the frequency characteristics of the sound generated by the guitar with modern sound holes are presented. Resonant frequencies of the soundboard were pointed as being responsible for the too high amplitude of sound in the 600-800 Hz frequency range. Using optimization and finite element method modelling, the best patterns of bracings were proposed to equalize the frequency spectrum and improve the sound of the instrument.

2

Lightweight floor screed with increased impact sound reduction

Pilch Adam, Duda Piotr, Rubacha Jarosław

Vibrations in Physical Systems

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2023

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Vol. 34, nr 1

art. no. 2023103

EN

Increasing users’ requirements force to provide better and better solutions for reducing impact sounds. A lightweight floor screed can be a favorable solution for existing buildings with limited ceiling load capacity, where typical highly effective floating floors are too heavy to be used. In the paper further development of the impact sound reduction measurement method for small lightweight floor screed samples is presented. In order to protect the top layer of the sample from the hammers of the tapping machine, a thin concrete layer was coupled with the sample. What is more, a thin layer of sand below the sample was tested in order to improve the connection between the sample and the concrete floor. Based on obtained results, the concrete top layer and the sand bottom layer reduce slightly the effectiveness of the screed but decrease the uncertainty of the results significantly.

3

Impact sound reduction measurement method for lightweight floor screed

Pilch Adam, Duda Piotr, Rubacha Jarosław

Vibrations in Physical Systems

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2021

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Vol. 32, nr 1

art. no. 2021114

EN

Development and implementation of a new product in the form of a lightweight screed with high impact sound reduction require a lot of measurements of different aggregates of lightweight elements and filling. The manufacturing process influences the final parameters of the solutions as well. This is why a method was developed, that allowed a comparison of many different samples within one measurement session. The measured samples must therefore be small and easy to move. In the paper, various possibilities of impact sound reduction measurements were analyzed being different variants of the normative methods and those existing in the literature on the subject. Based on the obtained results, it was shown that for lightweight floor screeds, sound pressure level measurement is more reliable than vibration acceleration measurements. The top vinyl layer used between the tapping machine and the sample did not influence the results significantly and protected the sample from being distorted by the tapping machine hammers.